A new Swedish trial suggests that taking a low daily dose of aspirin after colorectal cancer surgery can significantly reduce the risk of the cancer returning.
The study, led by Prof. Anna Martling at the Karolinska Institute, involved over 3,500 patients across Sweden, Norway, Denmark, and Finland. Researchers focused on patients whose tumours carried specific genetic mutations in the PI3K pathway, which make them more responsive to aspirin’s anti-cancer effects. Around 40% of colorectal cancer patients have such mutations.
Patients with these mutations were randomly assigned to take 160mg of aspirin daily or a placebo for three years after surgery. The results showed that those taking aspirin were 55% less likely to experience a cancer recurrence than those on placebo.
Aspirin appears to work by reducing inflammation, interfering with the PI3K pathway, and limiting the activity of blood platelets that can protect tumour cells from the immune system.
Prof. Martling emphasized the importance of genetic testing for colorectal cancer patients to identify those who could benefit from aspirin. She noted the drug is inexpensive and widely available, making it a potentially accessible preventive measure.
However, long-term aspirin use carries risks. In the trial, four patients experienced serious adverse events potentially linked to aspirin, including gastrointestinal bleeding, allergic reactions, and bleeding on the brain. One death may have been caused by the drug.
Dr. Catherine Elliott, of Cancer Research UK, said the findings support previous research, including the CaPP3 trial in people with Lynch syndrome, and highlight the need for further high-quality studies to determine who would benefit most from low-dose aspirin therapy.
Reference: New England Journal of Medicine.
